Means for the manufacture and refining of pulp



July 9, 1940. w. P. GRUENDLER 2,207,194

MEANS FOR THE MANUFACTURE AND REFINING OF PULP I Filed Sept. 7, 1937 Patented July 9, 1940 MEANS FOR THE MANUFACTURE AND REFINING OF PULP William P. Gruendler, University City, Mo., as-

signor of one-fifth to Charles D. Altick, Dayton, Ohio, and one-fifth to Lloyd D. Smiley, Jackson Heights, N. Y.

Application September '1, 1937, Serial No. 162,670

2 Claims. (01. 92-26) This invention relates to certain new and useful improvement in means for the manufacture and refining of pulp such as used in preparation of paper, board, felt, and made from rag and straw, wood chips or any suitable fibrous or vegetable stock.

Heretofore such pulp has been made by phy-' sical contact of wood against grindstones, rotary cutters, heaters, cone, disc and other similar devices. Even when the grain of said stock is disposed more or less parallel to the cutting or grinding action, the fibres of said stock are more or less damaged in their original length, and the paper made from said pulp is correspondingly weakened in strength. f

By my process and the means whereby I carry it out, substantially all of this damage to the fibres is avoided, since it consists in the use of a liquid such as water, projected at a high velocity against the fibrous stock so as to produce a bursting or explosive effect upon the stock.

I prefer to obtain this high velocity by the centrifugal action of a rotor having cup-shaped pockets or other suitable vanes which deliver liquid and fibrous stock substantially radially at a high peripheral speed of 18,000 feet or more per minute.

For example: a rotor of 18 inch diameter operating at 3800 R. P. M. will give substantial y 18,000 feet per minute peripheral speed. Likewise a rotor of 40 inch diameter at 1800 R. P. M. will give somewhat more than 18,000 feet per minute peripheral speed.

when working with fibrous stock and water under high pressure great centrifugal force is developed.

I have found in practical operation of my process with means similar to such hereinafter described, that the fibres produced from suitable fibrous stock are not damaged to any appreciable extent-only resinous and ligneous matter having been released and separated, leaving only the fibres at original or full length, whichresult has long been desired; and provides themeans of working with much rawer pulp, which produces the following effects A, obtaining a high tensile increase per H. P. hour; B, high Mullen increase per H. P. hr.; C, less tear drop per point Mullen developed; D, good formation at high freeness; E, littlefreeness drop per point Mullen developed; and F porosity and bulk can be greater per same weight sheet, and are the essential features commonly known in paper making and highly desired.

In the accompanyinl drawing in which like reference numerals indicate corresponding parts,

Fig. 1 represents a sectional elevation of a rotor A mounted in its casing for the primary defibration of the fibres, and connected in series with a similar rotor. C through an interposed stock 6 chest B;

Fig. 1a, a detail plan view of the curved throat;

Fig. lb, a sectional detail of the rotor shaft Packing;

Fig. 2, an end view of such a rotor in its cas- 1. ing and direct connected through a flexible coupling to a motor;

Fig. 3, a detail front view of the preferred form of cup-shaped vane as carried by said rotors; and Fig. l, a vertical central section of the same.

The preferred form of cup-shaped vane is shown in Figs. 3 and 4 and comprises a pocket P formed by a curved back I having aforwardly curved outer lip 5 and connected by comparatively thin sides 2. The lower portion is solid and has a hole 3 through which passes a supporting rod. This rod acts as a pivot in emergency, but in practice the high centrifugal force fixes the vane in position as no wear is apparent-in use. The adjacent inner wall portion of said pocket is curved down around and then radially outward from said pocket to a discharge edge 4 as shown in Fig. 4, leaving the opening of the cup from the edge 4 to the outer lip 5 to form an inlet 'into the cup for the liquid vehicle of the fibrous stock, and an outlet from the cup when discharged from said opening and thrown off said edge 4' by the centrifugal force developed by the rotation of said rotor. Y

, The outer lip 5 is located further out fromthe shaft I which is the center of rotation, than the edge 4. Also the forward curvature of the outer portion of the back wall adjacent this outer lip 5, tends to slice from the entering feed a portion of the mixture which then slides inward on the curved back wall until it reaches the rounded bottom end of the pocket and is reversed in its direction when it is discharged over the shorter edge 4. The high velocity given to this portion of the mixture by the vane, due to the high peripheral velocity of the cup-shaped vanes and' the centrifugal force to which the mixture is subjected, causes the mixture to leave the discharge edge l with great force in substantially radial direction outward from the cup. This action is the reverse of that of a turbine in which the force of the water is transmitted to the blades of the turbine, that is to say, in my process a high turbulent action is obtained and an immediate bursting efiect is had, thereby causing the fibres to. be separated instantaneously from'ligneous and resinous matter, and defibration to continue till the fibres are suitably refined for the desired use.

This vane may be of any other suitable form, and is supported by spaced disc plates 6 mounted on a rotor shaft 1 which is direct connected through a flexible coupling to a motor 8, Fig. 2, or otherwise. A casing 9 has a hopper throat forming an inlet, and an inner cage I I cooperating with said vanes. One wall face of this hopper inlet is formed by a hopper cross bar that is curved downward in said hopper and forward in the direction of rotation of the rotor, and is also curved laterally backward to form a center ridge In (Fig. 1a), to spread the entering feed across the rotor like a double plowshare. The axial length of the vane or series of them, is substantially that of the throat inlet so that substantially all the feed passes into the cup-shaped vanes.

This cage is provided with radial faces l2, and alternating inclined faces l3 respectively connecting said radial faces, so that the mixture of fibrous stock and its liquid vehicle entering by the hopper inlet of the machine A, is deflected inward again toward the rotatingvanes in successive cascade form, after the same has been projected outward from the vanes at said high velocity by said vanes of the rotor.

As shown by the drawing, there is such a space between the edges 5 of the vanes that the stock is not subject to any grinding action but only to the impact of liquid moving at high velocity as stated, and therefore substantially the orginal length of fibres is maintained without any grinding disintegration-only a separation of the fibres from the ligneous or other portions of the stock that originally binds the fibres in their original position therein. Also the radial and inclined faces l2-I3 respectively having the curved connecting surface l2 as shown in Fig. 1, allow the said mixture to glide along the radial faces I! and the inclined faces l3 and be reversed by the curved faces connecting the radial and inclined faces and form a cascade having approximately the original velocity given it by the high rotating speed of the cup-shaped vanes, although being somewhat diminished by the frictional contact of the mixture passing over the said surfaces. The mixture returned in cascade form is again intercepted by the cup-shaped vanes, increased in velocity, and again thrown centrifugally from the vanes at restored high velocity of substantially 18,000 ft. per min. (300 ft. per second), or more. It thus meets the mixture returning from the cage in reverse direction and only somewhat diminished in velocity. The resultingliquid vehicle impact of currents colliding from substantially opposite directions, provides a greatly increased liquid force that acts with corresponding effect upon the fibres in the mixture, and produces a corresponding increase of efficiency in the resulting separation of the fibres from ligneous and resinous matter.

This primary defibration of the fibres in the machine A, is transmitted by a pipe I 4 to a stock chestB having an agitator therein by which the mass of fibres is kept in suspension in the liquid vehicle which may receive additional liquid to make the mixture of proper consistency before passing out of said stock chest into the inlet of the machine C.

In this second machine the fibres aresubjected to the same high centrifugal action as in the machine A, but this refining machine is preferably provided with means to retard the outflow of the refined mixture till the fibres are of the required separation and refinement for the paper or other product for which'the pulp is to be used.

This retarding means consists of a vertical partition or dam I5 in one end of a chamber in the casing below the cage, and is, preferably in several widths so that the height of its top may be adjusted as desired. The outflow of the product refined in said machine through an opening dividing its cage and forming a free outlet I8 is thus regulated by said partition, so that the refined product is more or less retained in the cage and is backed up through said outlet for further operation according to the height of said dam l5. An inclined bottom trough l1 directs the mixture to the dam and the discharge pipe I8.

A valve l9 toward the front of the casing and at the opposite end of the chamber from the dam I of this machine 0, will admit additional water below the cage when required to maintain the desired consistency and to regulate the outward flow down said inclined bottom I1 and over the dam to the discharge pipe H3.

The turbulent and high velocity action of the liquid vehicle in the casing of these defibrating machines produces internal liquid pressure, tend.- ing to cause leakage where the rotor shaft enters the casing. To avoid such leakage and maintain internal pressure, I provide a stufilng box 20 of annular V-shape having a felt ring 2 I, of V.-shape or otherwise, one leg of which closely encircles the shaft and the other leg is adjustably held against the side of the casing by the corresponding face of the box 20, as indicated in Fig. 1b.

On account of the variations of hardness of different fibrous stock from which the fibres are obtained by defibration, a multiple number of such machines such as above described can be used in carrying out my process. I have shown and described two machines with interposed stock chests for maintaining the proper consistency of the water or other liquid and the fibres undergoing defibration. Also it is understood that suitable chemicals commonly used in digesters of pulp may be used as may be required for assisting in defibrating the fibres from the resinous and ligneous matter in the fibrous stock used.

Having thus fully described the process to which I subject the fibrous stock, I summarize the steps comprised in said process as follows:

Step a comprises subjecting fibrous stock to the impact of intercepted portions of liquid projected at high velocity.

Step 1) comprises projecting such liquid portions centrifugally at high velocity ranging from substantially 18,000 ft. or more per minute.

Step 0 comprises deflecting portions of the mixture of fibers and vehicle liquid reversely at high velocity.

Step d comprises creating successively a cascade of said mixture against successive centrifugally projected portions of mixed fibers and liquid.

Step e comprises projecting said portions of mixed fibers and liquid at a velocity substantially 18,000 ft. or more per minute for refining said fibers.

Step 1 comprises retarding the outflow of mixed fibers and vehicle liquid, lowering its consistency, again subjecting it to steps b, c, d and e for final refining, and discharging the refined product.

I claim:

1. A deflbrating machine, comprising a casing having a cage, and a rotor mounted for driving liquid material through the cage, the inher wall of said cage having a plurality of diverging faces joined together by a cylindrical concave portion, one of said faces extending approximately radially of the cage and the other of said faces being disposed at an obtuse angle to the first mentioned face, said rotor having pockets thereon, each of which has a forwardly curved outer lip and a radially extending edge connected by a curved intermediate portion to said lip.

2. A defibrating machine, comprising 9. cas ing having a cage, a rotor mounted for driving liquid material through the cage, the inner wall of said cage having a plurality of diverging faces joined together by a cylindrical concave portion, one of said faces extending approximately radially of the cage and the other face being disposed at an obtuse angle to the first mentioned face, said rotor having pockets thereon, each of of which has a forwardly curved outer lip and a radially extending edge connected by a curved intermediate portion to said lip, and means for controlling the outflow of liquid material from the cage.

WILLIAM P. GRUENDLER. 

